<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>重叠z-index</title>
		<style>
			.container{
				font-size: 6px;
				height: 20em;
				display: flex;
				margin: 4em;
				position: relative;
			}
			.container span{
				display: block;
				width: 20em;
				height: 20em;
				border-radius: 50%;
				position: absolute;
			}
			.container span:nth-child(1){
				left: 0;
				background-color: hsl(0, 90%, 70%);
				z-index: 4;
			}
			.container span:nth-child(2){
				left: 10em;
				background-color: hsl(30, 90%, 70%);
				z-index: 3;
			}
			.container span:nth-child(3){
				left: 20em;
				background-color: hsl(60, 90%, 70%);
				z-index: 2;
			}
			.container span:nth-child(4){
				left: 30em;
				background-color: hsl(90, 90%, 70%);
				z-index: 1;
			}
		</style>
	</head>
	<body>
		<div class="container">
			<span></span>
			<span></span>
			<span></span>
			<span></span>
		</div>
	</body>
</html>
